1. Field of the Invention
The present invention relates to a heating device, and more particularly to a heating device which is mounted on a pipe and which transfers its heat to the heating oil flowing therethrough.
2. Description of the Prior Art
Today, with the increasing scarcity of heating oil combined with the increasing demands for clean exhaust gases, i.e., free of harmful substances, an electrical preheating of the heating oil, for oil burners is desirable. Through the resultant reduction in the viscosity of the heating oil attained thereby, lesser charge quantities, for example under 1.4 kilograms per hour, can be dependably atomized. Further details of this matter can found in: feuerungstechnik (Fuel Engineering), May 1978, pages 13 through 30.
Especially for small installations, the oil burners which are commercially in general use today are designed so that they can be used over a relatively large range of desired thermal outputs. To accommodate the special needs of each individual customer requires only the installation of a particular nozzle and an adjustment of the air supply. If however, the oil burner also includes a resistance-heated electrical preheater, then this would have to be controlled in relation to the varying oil charge rate. This would create a significant difficulty for the operation of the burner. One would have to worry that a sufficiently high heating of the oil, for example to over 70.degree. C., is attained, and indeed a relatively fast attainment of the final state is required. However, in perhaps the case of a brief stand-still or during interruption of the oil feed, no oil overheating can be permitted to occur with the resulting vapor formation and the likely multi-phase conveyance problems associated therewith. An electrical heating by means of a filament winding would also make very expensive control electronics necessary. In spite of these problems however, the attempt is always being made to design such oil burner to be as simple as possible yet also reliable.
Thus the problem presented is to create a heating device for the preheating of heating oil which will, without any particular installation work, take care of an amount of the oil feed which ranges over an order of magnitude, which device can easily be installed in pre-existing oil burner installations, and which can be operated both at 110 volts at 220 volts without the necessity of a converter.